Method for determining cut point in pipe-line crude oil batching



Oct. 2, 195] R N MElNERT 2,570,064

METHOD FOR DETERMINING CUT POINT IN PIPE-LINE CRUDE OIL BATCHING Filed Sept. 6, 1947 1 LAMIPLIFIEK ANAQzaL I D gw 'Pms. LANE. M M

INFRAZED g LMClbborneg Patented Oct. 2, 1951 METHOD FOR DETERMINING ouTroIN'r IN PIPE-LINE CRUDE. on; BATCHING Richard N. Meinert, Tulsa, Okla., assignor to Standard Oil Development Company, a corporation of Delaware I Application September 6, 1947, Serial No. 772,518

2 Claims. 1

The present invention is concerned with an improved process for the transportation of various crudes through pipe-lines or the equivalent. This invention more particularly relates to a method for determining the time at which one batch of crude oil being pumped through a pipe-line has passed a given point, and the next batch is beginningto pass that point. My method enables the operator to determine when to switch his lines from one tank to another so as to segregate separate batches of crude with the minimum amount of contamination. In accordance with the present invention, an infra-red device utilizing a split beam is utilized to determine the end of one batch of crude oil and the beginning of the next batch in pipe-line operations.

It is well known in the art to transfer or transport various petroleum oils from one location to another by pipe-line operations. In most operations various crudes or oils having different characteristics are transported by means of suitable pumps, storage tanks and the like through the same pipe-line. One difiiculty encountered is that it is rather difiicult to spot the exact point or time when one crude has been fully received. This is usually determined by waiting until it is evident from visual sight that another crude is entering the receiving station. Lines are then switched and the following crude is directed to its proper receptacle or storage tank. Although the amount of contamination is maintained at a relatively low percentage by continual observation of the incoming crude, the contamination still in many instances is appreciable. On the other hand, the characteristics of many crudes as determined by observation cannot be differentiated by visual inspection, and in many instances a relatively large percentage of a contaminating crude finds its way into a preceding batch of crude being processed. This may in some instances call for a more intense or even a separate refining treatment in order to segregate the contaminates from the oil which has been transported. This is particularly the case when the petroleum oils are refined and have relatively high gravities.

I have now discovered a method wherein infrared radiation may be employed to determine when a crude or oil of different characteristics is entering or about to pass or enter a control point, which in most cases is the receiving station. The method enables an operator to determine when to switch his lines from one tank to another so as to segregate separate batches of crude with the minimum amount of contamination. The method furthermore enables the operator to determine 2 the extent of the area between the respective crudes which is contaminated with the preceding and following crude. The device utilizes a form of infra-red absorption apparatus based on the principle that different type of crude oil have difierent capacities for absorbing infra-red radi ation at selected wave length bands in the spectrum.

The invention may be readily understood by reference to the drawing illustrating one embodiment of the same. Referring specifically to the drawing, a continuous flow of petroleum oil fluid is passed through pipe-line l by a suitable pumping means. A continuous sample of the flowing fluid is withdrawn from pipe-line l by means of line 2. If desired a small pump or other suitable means may be employed to secure a continuous flow of the pipe-line oil through line 2. Valves H, l2, [3' and I4 are opened and a stream from line 2 is allowedto fill up and flush cells A'and B. Excess fluid from the cells is withdrawn through lines 3 and 4 and passed through stopcocks l3 and I4 back into line I. Valves I l and M are then closed leaving cell B filled with the fluid in the pipe-line, which for thepurpose of description is designated Batch X. Cell B serves as the reference cell. Batch X fluid continues to flow from the line to and through cell A. -As the next batch of crude oil Y begins to come through the pipeline, cell A becomes filled with this batch of Y fluid which has a diiferent infra-red absorptive coefficient. This results in a change in the energy falling on detector G1 and a consequent unbalance in signals, which is indicated on the recorder l5. This warns the operator that the batch is changing and that batch Y is to be switched to a different storage tank.

Referring specifically to the mechanism of the infra-red analyzer, the operation is as follows. The infra-red analyzer consists of a light source, S, which may be a globar, energy from which is directed in a more or less parallel beam through filter cell F and cells A and B by means of a pair of curved mirrors M1 and M2 respectively.

These mirrors are preferably ofi-axis parabolas, but since sharp focusing is not critical, they may be spherical. The reflected light passes through the adjustable diaphragms D1 and D2, then through the filter cell F which contains a suitable absorbing medium. Cell F will pass a relatively wide band of infra-red radiation in the desired spectral region or regions. One beam of light then passes through cell A, through which a portion of the pipe-line stream continuously passes as hereinbefore described. This r 3 light is focused by mirror M3 on detector G1 which may be any type oi. suitable detector. For example, detector G1 may be a thermopile, a bolometer, or any conventional infra-red detector. The other beam of light passes through the reference cell B which is filled with the reference fluid as hereinbefore described. It is to be noted that no fluid is flowing through cell B at the time. The light is focused by mirror M4 on detector G2.

The signals from detectors G1 and G2 are opposed in a balancing electrical circuit which is so arranged that any signal resulting' fro'm offbalance of the system is fed to an amplifier l6 and thence to a recorder as shown. Alt'erna'- tively, the amplified signal may be fed to an indicating device such as a galvanometer. The two optical beams should be so arranged'that they are as nearly symmetrical as possible. Balance is preferably adjusted by opening or closing the di'a'phragms D1 and Dz. If desired, a light chopping device may be interposed in the light beam so as to produce a fluctuating energy pulse in'each detector. The resulting impulse or signal may then be amplified by an A.-C.- type of amplifier. During the movement of batch Y the above procedure of fillin cells A and B is followed through so that cell A is full of batch Y and acts as the reference cell, through which no fluid is flowing. Batch Z will be immediately picked up inv accordance with my device by changing the balance of input into the galvanom'eter, since batch Z when it enters cell B will not have the same infra-med absorptive abilityas batch Y.

My invention is generally directed toward the use of an infra-red analyzer to determine when one batch of "crude oil has passed and another is about to enter-the control point. In accordance with my-process, one cell serves asa reference cell while a'portion of the flowing liquid is allowed to pass through the second cell. These two cells are" connected in a balanced electrical circuit; As a crude of different characteristics enters the second cell, the infra-red absorption will be difi'erent, thus unbalancing the circuit, which may readily be made apparent to an operator.

The process of my invention is not to be limited by any theory as to mode of operation, but only 4 in and by the following claims in which it is desired to claim all novelty insofar as the prior art permits.

What is claimed is:

1. In the transportation of petroleum liquids through pipelines, wherein separate batches of different liquids are passed successively through the same pipeline, the method of detecting a batch change at a selected point in the line which comprises initially placing in two detectin zones portions of the batch of liquid then flowing through the pipeline at the point selected, passing infra-red radiation through the two detection zones, detecting transmitted infra-red radiation from each zone and converting the radiation from each zone into an electrical quantity, balancing the electrical quantities from the two zones in an electrical circuit, continuously passing liquid through one of said zones as a side stream from the main body of liquid passing through the pipeline while maintaining the original portion of liquid in the second zone, continuously passing infra-red radiation through both of said zones and detecting a shift in balance of the electrical circuit as an indication of a batch change in the liquid passing through the pipe line. 7

2. Method according toclaim 1 in which con tinuity of batch change detection is maintained by promptly cutting off flow of liquid in the first detection zone after a batch change has occurred, conducting a side stream of the new batch of liquid then passing through the pipeline, at the selected point, through the second detection zone, rebalancing the electrical circuit, and thereafter detecting the next batch change the manner set forth. 7

- I RICHARD ,N. MEINERT.

REFERENCES CITED p The followingv references are of record in the file of this patent:

UNITED STATES PATENTS 

